The present invention is directed to battery charging arrangements and, more specifically, to arrangements for supplying a charge from a towing vehicle battery to a battery for equipment being towed or trailered by the towing vehicle.
There have been previous approaches to charging batteries, including those mounted on a towed vehicle. Examples of such approaches are described in U.S. Pat. Nos. 4,647,139 (Yang), 4,649,332 (Bell), 4,829,223 (Broberg), 4,885,524 (Wilburn), 5,013,259 (Maurer), 5,583,414 (Lawrence), and 6,166,516 (Albright). One approach to remote-battery charging includes an electrical circuit having a diode connected in series with a resistor having a resistance value within the range of 200 to 235 ohms. These components are electrically connected in series between the charging source, which is typically the positive terminal of the battery of the towing vehicle, and the positive terminal of the battery on the towed vehicle which needs to be charged. At the beginning of charging operation, the towed vehicle battery is often relatively discharged and the current draw from the towed vehicle battery is relatively significant. After a period of time, as the diode passes the current, the towing vehicle electrical system charges the towed vehicle battery, and the current draw from the towed vehicle battery is reduced. The high-wattage resistor that is used to reduce the current generated in the charging circuit may be large enough to result in a hazardous condition (e.g., excess heat, possibly causing a fire), particularly when the towing vehicle battery and the towed vehicle battery are improperly connected in reverse polarity, which creates a 24-volt potential, or when the battery on the towed vehicle becomes internally short-circuited. Although use of a high-wattage current-limiting resistor protects against such a potentially hazardous condition, a major drawback of this system is that, by including a relatively high resistance in the circuit, the normal or typical charging current is so small that the towed battery receives very little charge, even over long periods of time; this reduction in charge is directly due to the resistance and associated voltage differential across the diode/resistor combination and, to a lesser extent, the inherent resistance of the cables used to interconnect the batteries. Depending upon these resistance values, the rate of charge can be relatively insubstantial and, for relatively short towing trips, unacceptable.
Other disadvantages with the above approaches involve manufacturing, installation and ease of use. Requiring both a resistor and a diode to implement the charging arrangement results in higher material costs during manufacturing, and increases the complexity of installation. Moreover, increasing the complexity of installation increases the risk of improper installation. Another related need is a way to encourage and remind the user to connect the trailered battery for charging; attempting to use the trailered equipment on site without a charged battery for the equipment can be very frustrating.
Accordingly, these and other design considerations have presented challenges to efforts to implement an approach to charging towed vehicle batteries that is relatively inexpensive and also capable of providing an adequately high charge rate.
The present invention is directed to overcoming the above-mentioned challenges and others related to the types of devices and applications discussed above and in other memory cells. The present invention is exemplified in a number of implementations and applications, some of which are summarized below.
According to an example embodiment of the present invention, an arrangement charges an equipment battery while the equipment is being towed by a towing vehicle. The towing vehicle has a primary battery and a rearward-located hitch for towing the trailer that carries the equipment battery. The arrangement includes three sets of electrical lines, each with terminals conveniently adapted for ease of use. A front set of main electrical lines includes terminals at one end thereof for electrically coupling to the anode and cathode of the primary battery and includes a main plug-in adapter at another end thereof. A rear set of rear electrical lines includes terminals at one end thereof for electrically coupling to the anode and cathode of the secondary battery and includes a trailered plug-in adapter at another end thereof. An intermediary set of interconnecting electrical lines includes a first plug-in adapter at one end thereof for plugging into the main plug-in adapter and electrically coupling to the primary battery and a second plug-in adapter at another end thereof for plugging into the trailered plug-in adapter and electrically coupling to the secondary battery. Also, line harnesses are included to secure the electrical lines during periods of towing.
In other example embodiments a circuit breaker and/or a power-on indicator are provided in-line.